Telephone system.



U. S. WINSTON. TELEPHONE SYSTEM.

APPLICATION FILED NOV. 22. 1901.

Patented Aug. 16, 1910.

1n: mmms PETERS ca.. wAsHmcra/v, n. c.

'onrrno STATES PATENT OFFICE.

CHARLES S. WINSTON, OF CHICAGO, ILLINOIS, ASSIGNOR 'IO KELLOGGSWITCI-IBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A. CORPORATIONOF ILLINOIS.

TELEPHONE SYSTEM.

To all whom it may concern:

Be it known that I, CHARLES S. WINSTON, a citizen of the United States,residing in Chicago, county of Cook, and State of Illinois, haveinvented certain new and useful Improvements in Telephone Systems, ofwhich the following is a specification.

My invention relates to telephone systems, and particularly to that typehaving a central battery to supply current for the operation of thetransmitters at the various substations.

The object of my invention is to simplify the circuits of thesignal-controlling apparatus at the central ofiice to produce a systemwhich shall be inexpensive to manufacture and install and simple tomaintain.

My invention is illustrated in the accom panying drawing, certain partsof which are shown in rather more conventional form than would be usedin actual practice, it being understood that these parts form no partofmy invention, and that many other forms of apparatus may be substitutedin lieu thereof.

The calling subscribers station 1 is equipped with the usual transmitter2, receiver 3 and switch-hook 4, in a normally open bridge between theline conductors 5 and 6. In a permanent bridge between these conductorsare connected an annunciator 7 and a condenser 8, the latter being inseries and adapted to be placed in parallel with the transmitter andreceiver when the switch hook is moved to its abnormal position. Linewires 5 and 6 extend respectively to the spring contacts 10 and 11 ofthe cut-off relay 12 located at the central office. The spring 10normally makes contact with the point 13 which is connected through thecoil of line relay 14 with the live pole of battery The spring 11 of thecut-off relay 1s normally connected through the contact 15 with theground pole of battery A. The normally open contact 16 of cut-off relay12 is connected with the coil of said relay and through conductor 17with the test contacts 18 of the multiple jacks which are individual tothe line of subscriber No. 1. The other normally open contact 19 ofcut-off relay 12 is connected through conductor 20 with the tip contacts21 of the multiple jacks. Line relay 14 controls the normally openSpecification of Letters Patent.

Application filed November 22, 1907.

Patented Aug. 16, 1910.

Serial No. 403,290.

contacts 22 and 23 in the circuit of line lamp 24 such that upon theactuation of relay 14 the said lamp is lighted.

The answering substation No. 1 shown upon the left is equipped withsimilar apparatus to that of line No. 1, and correspond ing apparatusassociated with this line both at the substation and at the centraloffice is represented by like figures with the suflix The cord circuitused by the operator for connecting the calling line with a called-forline is provided with the answering plug having the tip contact 25connected through the conductor 26, condenser 27, conductors 28 and 29with the tip contact 30 of the calling plug. Similarly, the sleevecontact 31 of the answering plug is normally connected through the coilof relay 32, conductor 33, condenser 34, coil of relay 35 and conductor36 with the sleeve contact 37 of the calling plug. The main battery A isconnected in a bridge of the talking strands of this cord cir' cuit bythe coils of the tip supervisory re lays 40 and 41 and the retardationcoil 42 and the coil of relay 43.

The answering end of the cord circuit is provided with the supervisorylamp 44 in a circuit normally maintained open by the contacts 45 and 46of relay 32. The tip supervisory relay 40 controls normally-opencontacts 47 and 48 adapted when closed to complete a non-inductive shuntof low resistance about the coil of relay 32. The calling end of thecord circuit is similarly provided with the supervisory lamp 50 in acircuit maintained normally open by contacts 51 and 52 of relay 35, thetip supervisory relay 41 similarly controlling the contacts 53 and 54 inthe normally open shunt about the relay 35. The tip contact 30 of thecalling plug is normal-1y connected by conductor 29 and the normalcontacts 55 and 56 of relay 43 to the normally open contacts 57 and 58of the operators listening key 59. Contact 58 is connected with oneterminal of the impedance coil 60 and with the condenser 61, the otherterminal of the impedance coil being connected with ground, and theother terminal of the condenser being connected through the tertiarywinding 62 of the operators induction coil 63 with the live pole ofbattery A. Relay 43 also has the normally open contact 53 adapted to beengaged by the spring 55 to disconnect the contact 56 and complete thecircuit between conductors 2S and 29. The actuation of the operatorslistening key 59 also places the operators head receiver 65 in a shuntbetween the talk ing conductors of the cord circuit, this shunt alsoincluding the condenser 66 and the secondary 67 of the operatorsinduction coil 63. This induction coil 63 also has the primary winding68 connected with the transmitter 69 and with any suitable source ofcurrent not shown.

The operators ringing key has normally closed contacts in the circuit ofeach strand of the talking circuit adapted to be broken by the actuationof the key to prevent ringing current from passing back over the cordcircuit to the calling subscriber. hen the key is fully actuated the tipspring 71 makes contact with the ringing current contact 72 whichconnects with 'a suitable source of current 73. The sleeve spring of theoperators ringing key when fully actuated connects with the contact 76which is in turn connected by the non-inductive resistance 77 with thelive pole of battery A.

In the operation of the system here described the subscriber in chargeof substa tion No. 1 removes his receiver from its hook, therebycompleting a circuit from the live pole of battery A through the coil ofline relay 14, contacts 13 and 10 of relay 12, conductor 5, transmitter2, receiver 3, switch hook 4, conductor 6 and springs 11 and 15 of relay12 to earth. The current in this path actuates relay 14 closing contacts22 and 23 and completing the circuit of the line lamp 24. The operatorseeing line lamp 24 displayed, inserts her answering plug in the jackindicated by the display of lamp 24 and thereby completes a circuit fromthe live pole of battery A through the retardation coil 42, coil ofrelay 32, sleeve contact 31 of the answering plug, contact 18 of theack, conductor 17 and the coil of cut-oft relay 12 to ground. Current inthis path actuates relays 32 and 12, the latter changing its springs 10and 11 to their abnormal positions whereby they make contact with thepoints 16 and 19. The momentary energization of relay 32 may close thecontacts 45 and 46 in the circuit of the supervisory lamp 44 and therebytend to display the lamp. However, immediately upon the actuation ofcut-oft relay 12 the circuit of relay 14 is broken by the separation ofcontacts 10 and 13 of relay 12 and a new circuit is completed from thelive pole of battery A through the retardation coil 42, coil of relay32, sleeve contacts of the plug and jack, contacts 16 and 10 of thecut-oil relay, the line wire 5, transmitter 2, receiver 3, switch-hook 4and line wire 6 through the now closed contacts 11 and 19 of relay 12,tip contacts 21 and 25 of the jack and plug and the coil of relay 40 tothe ground pole of battery A. Current in this path immediately actuatesrelay 40, closing its contacts 47 and 4H and placing a shunt about thecoil of relay 32 and causing that relay to be immediately dcenergizedwhich prevents the lamp 44- from being more than just momentarilyactuated if its circuit is kept closed long enough to display the lampat all. The operator now throws her listening key 5!) and places herhead receiver 65 in a bridge of the talking circuit between the tip andsleeve conductors and inquires the desired number. Upon obtaining thedesired number and before releasing her listening key, the operatorraises her calling plug and touches the tip 30 to the test contact 18 ofone of the multiple jacks of the desired line. It the desired line isbusy the contact 18 will he at a potential higher than ground andcurrent will therefore flow over the tip through the normallyclosedcontacts of the ringing key,co1nluctor 29, contacts 55 and 56 of relay43, contacts 57 and 58 of the listening key through the impedance coil60 to ground. This sudden flow of current will alter the potential atthe terminal of the impedance coil (30 and produce a partial dischargeof condenser 61, causing a disturbance in the tertiary winding 62 of theoperators induction coil 63. This disturbance causes a click in theoperators head receiver indicating to the operator that the line isbusy. If the line is not busy no click will be heard and the operatorwill insert the plug in the jack of the desired line.

Assuming the line to have been idle, and the calling plug inserted inthe desired line, the operator now throws her ringing key 70 in order tocall the desired subscriber. When this key is thrown current from thelive pole of battery A flows through the non-inductive resistance 77,contacts 76 and 75 of the ringing key 70, sleeve contacts 37 and 18 ofthe plu and jack, conductor 17 and the coil of relay 12 to ground.Current in this path actnates relay 12 closing its springs 10' and 11against the normally open contacts 16 and 19. The actuation of theringing key 70 also connects the tip spring 71 with the ringing currentcontact 72, thus closing a path for ringing current from the generatorover the tips 30 and 21 of the plug and jack, over conductor 20,contacts 19 and 11 of relay 12, conductor 6, condenser 8, annunciator 7,line conductor 5, and contacts 10 and 16 of relay 12, conductor 17,sleeve contacts 18 and 37 of the jack and plug, spring 75 and contact 76of the ringing key 70, non-inductive resistance 7 7, through the batteryA to ground and thence baclf to the generator 73. This current operatesthe annunciator 7 and calls the desired subscriber to his telephone.Upon the release of key 70 the cirthe 0011 of relay 35, conductor 36,the closed contacts of the ringingkey 70, sleeve contacts 37 and 18 ofthe plug and jack, conductor 17 and the coil of cut-oft relay 12. 1Current in this path maintains the actuation of relay l2 and 43 and 35,the latterZ closing its contacts 51 and 52 which com- 1 pletes thecircuit of the supervisory lamp 50. The display of this lamp indicatesto the operator that the called subscriber has not yet answered hiscall. The actuation of relay 43 moves its armature 55 into contact withthe point 53, thereby disconnecting the test apparatus and completingthe circuit of the tip strand between the conductors 29 and 28. When thecalled subscriber removes his receiver 3' from the hook switch 4, hecompletes a circuit from the live pole of battery A through the coil ofrelay 43, the coil of relay 35, conductor 36, sleeves 37 and 18 of theplug and jack, conductor 17, contacts 16 and of cut-off relay 12, lineconductor 5, transmitter 2, receiver 3 and hook-switch 4, line conductor6, contacts 11 and 19 of cut-oif relay 12, conductor 20, tip contacts 21and of the jack and plug, conductor 29, contacts 55 and 53 of relay 43,conductor 28 and the coil of relay 41 to the ground pole of battery A.Current in this path actuates relay 41, closing its contacts 53 and 54which complete a shunt about the coil oi relay causlng the contacts ofthat relay to fall back to open the circuit of the supervisory signal50. The system is now in condition for conversation and all signals atthe central office are effaced. When either subscriber hangs up hisreceiver he breaks the circuit of relay or 41 as the case may be,causing that relay to fall back and re move the shunt about the coil ofrelay 32 or 35 as the case may be. When the shunt is removed from aboutthis relay the circuit is again completed through its coil and thearmature 45 or 51 is pulled up, completing the circuit of supervisorylamp 44 or 50. When these lamps are both displayed the operator removesher plugs from the jacks and again severs the circuits of relays 32 and35 and thereby again eifaces the supervisory lamps 44 and 50. Theapparatus is then in its normal condition and ready for a second call.

While I have shown and described my invention with respect to certaindetails and combinations, it is to be understood that I do not wish tobe unduly limited thereto, other combinations being quite possiblewithout in any manner departing from the spirit or scope of myinvention.

I claim:

1. In a telephone system, the combination with a telephone line, of acut-off relay for the line actuated over a portion of the talkingcircuit and a third conductor, a cord circuit, a source of currentassociated therewith, a supervisory signal, a relay controlling normallyopen contacts in the circuit of said signal, said relay being actuatedby current over a strand of the talking circuit and throughthe coil ofsaid cut-off relay when the cord is connected with the line, a secondrelay in a bridge of the talking strands of the cord circuit actuatedover the telephone line when the subscribers telephone is in use andcontrolling a normally open shunt about the first relay, whereby saidfirst relay is deprived of current and the super visory signal iscontrolled, substantially as described.

2. In a telephone system, the combination with a telephone lineterminating at the central office in a two-conductor jack, atwoconductor cord to connect therewith, a relay having its coil normallyin one of the strands of said cord circuit and adapted to be actuatedwhen the cord is connected with the line, a second relay in a bridge ofthe talking strands of the cord circuit controllin a shunt about thefirst relay and adapted to be actuated when the cord is connected to aline closed at the substation, and a supervisory signal controlled bycontacts of the first relay, substantially as described.

3. In a telephone system, the combination with a telephone line, of acord circuit to connect therewith, a relay, a source of current and animpedance coil in a bridge of the talking strands of said cord circuit,a second relay having its coil normally in series with one of thetalking strands of said cord circuit, a shunt of said relay controlledby contacts of the first relay and adapted when closed to deprive thesecond relay of actuating current and to complete a non-inductive pathfor voice currents about the coil of said second relay, and asupervisor-y signal controlled by contacts of the second relay,substantially as described.

4. In a telephone system, the combination with a telephone line, of acut-off relay for the line actuated over a portion of the talkingcircuit, acord circuit to connect with the line, a relay, a source ofcurrent and an impedance coil in a bridge between the talking strands ofsaid cord circuit, a second relay having its coil normally in serieswith one of the strands of the cord circuit and adapted to be actuatedover a path including a portion of the talking circuit and the coil ofsaid cut-off relay when the cord is connected with the line, normallyopen contacts of said first relay adapted when closed to complete anon-inductive shunt about the second relay to deprive it of current, anda supervisory signal cont-rolled by contacts of said second relay,substantially as described.

5. In a telephone system, the combination lays being in a bridge of thecord circuit,;

and contacts of the latter relay controlling a normally opennon-inductive shunt about F the first relay, and a supervisory signalcon- 1' trolled by the first relay, substantially as described.

Signed by me at Chicago, county of Cook, and State of Illinois, in thepresence of two witnesses.

CHARLES S. \VINSTON. Vit-nesses CLIFFORD C. BRADBURY, EDITH F. GRIER.

